1. Technical Field
The present invention relates to a graphene transparent electrode and a method for manufacturing the same.
2. Description of the Related Art
In general, graphite has a structure in which flat second dimensional graphene sheets each composed of carbon atoms linked in hexagonal shapes are stacked. Recently, it was found that one or several layers of graphene sheets peeled off from the graphite have very useful properties different from those of the existing materials, as the result of researching characteristics of the sheets.
The most notable property is that electrons flow in the graphene sheet as if the mass of the electron is zero, and this means that the electrons flow at a speed at which light moves in a vacuum, that is, at the speed of light. In addition, the graphene sheet exhibits an abnormal half-integer quantum hall effect with respect to electrons and holes.
Meanwhile, the existing silicon based semiconductor process techniques make it impossible to manufacture semiconductor devices having high integration density of 30 nm or less. The reason is that, in a case where a metal atom layer of gold or aluminum deposited on a substrate has a thickness of 30 nm or less, metal atoms are not thermodynamically stable, so that they adhere and stick together, thereby failing to obtain a uniform thin film, and the concentration of impurities doped in silicon is not uniform in the nano-sized thin film. However, the graphene has a chance to overcome the limitation in the integration degree of this silicon-based semiconductor device technique.
The graphene has metallic properties and the thickness thereof is very small, which has several nanometers or less corresponding to a screening length. Therefore, in the graphene, a charge density is changed depending on gate voltage, resulting in changing electric resistance. Accordingly, a metal transistor may be embodied by using the above properties, and a high-speed electronic device may be embodied by using high mobility of a charge transporter. Further, the graphene is expected to be applied in various fields because charges of the charge transporter are changeable from electrons to holes depending on the polarity of the gate voltage.
A plurality of methods or processes for producing the graphene having these performances per se have been disclosed in Korean Patent Registration No. 10-0819458 and the like. In addition, Korean Laid-Open No. 10-2011-0016287 discloses a coating method of graphene oxide, according to which a colloidal graphene oxide solution is coated on a surface of a substrate, followed by drying and then heat treatment, and thus, the graphene oxide is converted to a graphene thin film, and this method has an effect that the graphene is directly coated on the surface of the substrate.
However, the graphene thin films disclosed in the patents are formed by complicated processes, and they are economically disadvantageous and exhibit low electric conductivity.